A.S. Lindner et al. / Tetrahedron 65 (2009) 7591–7596
7595
2.52 (br s, 4H,
b-Pip-H), 2.76 (br s, 4H,
a
-Pip-H), 3.94 (s, 2H, CH2),
3.5.8. 3-(2-Methoxyacetyl)-1-phenyl-1H-imidazo[1,2-a]-
7.12–7.30 (m, 2H, Harom.), 7.45–7.66 (m, 6H, Harom.), 10.23 (d,
pyridinium-2-olate (10g)
J¼6.8 Hz, 1H, 5-H). 13C NMR: (50 MHz, CDCl3):
d
¼44.9 (CH3), 52.6
Methanol was used; yield: 0.127 g (0.45 mmol, 90 %); mp:
(2C,
a
-Pip-C), 53.9 (2C,
b
-Pip-C), 62.5 (CH2), 102.0 (C-3), 105.7 (C-8),
181 ꢀC; 1H NMR (200 MHz, CDCl3):
d
¼3.54 (s, 3H, CH3), 4.76 (s, 2H,
115.6 (C-6), 126.1 (2C, C-20), 128.4 (C-40), 129.0 (C-5), 129.0 (2C, C-
CH2), 7.13–7.27 (m, 2H, Harom.), 7.43–7.65 (m, 6H, Harom.), 10.82 (d,
30), 130.9 (C-10), 131.1 (C-7), 135.6 (C-9), 157.3 (C-2), 183.8 (C]O). IR
J¼6.4 Hz, 1H, 5-H). 13C NMR (50 MHz, CDCl3):
¼59.4 (CH3), 75.2
d
(KBr):
n
¼ 3423, 3111, 3039, 2963, 2927, 2791, 1678, 1613, 1510,
(CH2), 101.8 (C-3), 106.8 (C-8), 116.7 (C-6), 127.0 (2C, C-20), 129.4 (C-
~
1449, 1344, 1262, 1204, 1101, 1016, 801, 768, 710 cmꢁ1. MS: 351
[MþHþ](60), 280 (20), 252 (90), 237 (30), 223 (40),113 (50), 77 (35),
70 (100). HR-ESI-MS calcd for C20H23N4O2: 351.1821; found:
351.1821. Anal. cCalcd for C20H23N4O2: C, 65.20; H, 6.56; N, 15.20.
Found: C, 64.84; H, 6.19; N, 15.17.
40), 129.7 (C-5), 129.9 (2C, C-30), 131.8 (C-10), 132.2 (C-7), 136.8 (C-9),
~
n
158.2 (C-2),184.4 (C¼O). IR (KBr):
¼ 3442, 3107, 3060, 2988, 2945,
2825,1690,1604,1507,1476,1458,1440,1358,1323,1242,1202,1107,
1044, 997, 905, 770 cmꢁ1. MS: 283 [MþHþ](100), 267 (20), 252 (40),
237 (90), 181 (20), 77 (40). HR-ESI-MS calcd for C16H15N2O3:
283.1083; found: 283.1084. Anal. cCalcd for C16H14N2O3 (282.29): C,
68.07; H, 5.00; N, 9.92. Found: C, 67.74; H, 4.51; N, 10.02.
3.5.5. 3-(2-(Benzylamino)acetyl)-1-phenyl-1H-imidazo[1,2-a]-
pyridinium-2-olate (10d)
Benzylaminewasused; yield:0.109 g (0.31 mmol,62%); mp:148–
3.5.9. 3-(2-Allyloxyacetyl)-1-phenyl-1H-imidazo[1,2-a]-
pyridinium-2-olate (10h)
150 ꢀC; 1H NMR (200 MHz, CDCl3):
d
¼2.61 (s, 1H, NH), 3.89 (s, 2H,
CH2), 4.15 (s, 2H, CH2), 7.05–7.65 (m, 13H, Harom.), 10.15–10.19 (m, 1H,
5-H).13C NMR (50 MHz, CDCl3):
¼53.7 (CH2), 55.5 (CH2),102.4 (C-3),
106.7 (C-8),116.6 (C-6),126.8(C-8 , C-
),127.1 (2C, C-20),128.3(4C, C-6
), 129.4 (C-40), 129.7 (C-5), 130.0 (2C, C-30), 131.8 (C-10), 132.1 (C-7),
Allylalcohol was used; yield: 0.141 g (0.46 mmol, 92 %); mp:
d
126–129 ꢀC; 1H NMR (200 MHz, CDCl3):
d
¼4.20 (dt, J¼5.8, 1.2 Hz,
*
*
2H, 1
*
-H), 4.83 (s, 2H, CH2), 5.17–5.40 (m, 2H, 3 -H), 5.92–6.12 (m,
*
7
*
1H, 2
*
-H), 7.12–7.28 (m, 2H, Harom.), 7.41–7.64 (m, 6H, Harom.), 10.16–
136.6 (C-9),140.3 (C-5
*
),158.2 (C-2),186.4 (C]O). IR (KBr): ¼ 3334,
10.20 (m, 1H, 5-H). 13C NMR (50 MHz, CDCl3):
(CH2), 101.8 (C-3), 106.7 (C-8), 116.7 (C-6), 117.5 (C-3
20),129.3 (C-40),129.7 (C-5),130.7 (2C, C-30),131.8 (C-10), 132.1 (C-7),
d¼72.5 (C-1 ), 72.6
*
~
n
3054, 2926, 1667, 1606, 1511, 1439, 1239, 1206, 1057, 756, 710 cmꢁ1
.
*
), 127.0 (2C, C-
MS: m/z (%)¼358 [MþHþ](60), 266 (30), 252 (100), 237 (30), 210 (70),
181 (20), 91 (70), 77 (20). HR-ESI-MS calcd for C22H19N3O2: 358.1556;
found: 358.1557. Anal. cCalcd for C22H19N3O2$1H2O: C, 70.38; H, 5.64;
N, 11.12. Found: C, 70.61; H, 4.78; N, 11.02.
134.6 (C-2 ), 136.7 (C-9), 158.1 (C-2), 184.5 (C]O). IR (KBr):
*
~
n
¼ 3424, 3057, 2859,1688,1507,1456,1337,1239,1204,1118,1046,
904, 767, 713 cmꢁ1 MS: 309 [MþHþ](100), 252 (90), 237 (85), 223
(15), 210 (20),181 (30), 77 (80). HR-ESI-MS: calcd for C18H16N2O3Na:
331.1059; found: 331.1068. Anal. cCalcd for C18H16N2O3: C, 70.12; H,
5.23; N, 9.09. Found: C, 69.61; H, 5.25; N, 8.79.
3.5.5.1. Aliphatic alcohol derivates. Portions of 0.056 g (2.4 mmol)
of sodium were dissolved in 10 mL of the corresponding alcohols.
Then, 0.143 g (0.5 mmol) of the betaine 6 was added and the re-
action mixture was refluxed for 3 h. Evaporation of the solvent in
vacuo gave solids which were purified by flash column chroma-
tography [silica, ethyl acetate] to give the products 10e–g.
3.5.10. 3-(2-Phenoxyacetyl)-1-phenyl-1H-imidazo[1,2-a]-
pyridinium-2-olate (10i)
A sample of 0.286 g (1 mmol) of the betaine 6 was dissolved in
15 mL of anhyd ethanol. After addition of 0.138 g (1 mmol) of K2CO3
and 0.094 g (1 mmol) of phenol the reaction mixture was refluxed
for 4 h. Evaporation of the solvent in vacuo gave a solid residue
which was purified by flash column chromatography [silica gel,
ethyl acetate] to give product 10i.
3.5.6. 3-(2-Isopropoxyacetyl)-1-phenyl-1H-imidazo[1,2-a]-
pyridinium-2-olate (10e)
iso-Propanol was used; yield: 0.032 g (0.103 mmol, 21%) mp:
126 ꢀC (dec); 1H NMR (200 MHz, CDCl3):
d
¼1.27 (d, J¼6.2 Hz, 6H,
CH3), 3.73–3.86 (m, 1H, CH), 4.82 (s, 2H, CH2), 7.11–7.26 (m, 2H,
Harom.), 7.44–7.65 (m, 6H, Harom.), 10.09 (d, J¼4.6 Hz, 1H, 5-H). 13C
Yield: 0.111 g (0.32 mmol, 32 %); mp: 203 ꢀC (dec); 1H NMR
(200 MHz, CDCl3):
7.14–7.35 (m, 4H, Harom.), 7.46–7.67 (m, 6H, Harom.), 10.16 (dt, J¼6.6,
1.0 Hz, 1H, 6-H). 13C NMR (50 MHz, CDCl3):
d
¼5.39 (s, 2H, CH2), 6.90–7.09 (m, 3H, Harom.),
NMR (50 MHz, CDCl3):
d
¼22.0 (2C, CH3), 71.0 (CH), 72.2 (CH2), 101.9
(C-3), 106.7 (C-8), 116.7 (C-6), 127.0 (2C, C-20), 129.3 (C-40), 129.7 (C-
d¼70.0 (CH2), 102.0 (C–
5), 129.9 (2C, C-30), 131.8 (C-10), 132.0 (C-7), 136.7 (C-9), 158.1 (C-2),
C]O), 106.9 (C-3), 114.7 (2C, C-II), 116.8 (C-5), 120.8 (C-IV), 127.1
(2C, C-20), 129.3 (2C, C-III), 129.5 (C-40), 129.9 (C-6), 130.1 (2C, C-30),
131.7 (C-10), 132.5 (C-4), 137.1 (C-2), 158.6 (C-I), 163.1 (C–Oꢁ), 182.3
~
~
185.2 (C]O). IR (KBr):
n
¼ 3424, 3111, 3053, 2970, 2925, 1691,
1608, 1508, 1454, 1362, 1318, 1240, 1124, 763, 712 cmꢁ1. MS: 311
[MþHþ](50), 267 (40), 252 (100), 237 (100), 210 (20), 181 (30), 77
(60). HR-ESI-MS calcd for C18H19N2O3: 311.1396; found: 311.1396.
Anal. cCalcd for C18H18N2O3 (310.35): C, 69.66; H, 5.85; N, 9.03.
Found: C, 69.11; H, 5.43; N, 9.13.
(C]O). IR (KBr):
n
¼ 3424, 2924, 1675, 1609, 1504, 1456, 1300,
1266, 1235, 1207, 1081, 1053, 1028, 901, 752 cmꢁ1. MS: 344
[Mþ](90), 237 (100), 210 (80), 181 (40), 169 (20), 94 (15), 77 (90).
HR-ESI-MS calcd for C21H16N2O3Na: 367.1059; found: 367.1063.
Anal. cCalcd for C21H16N2O3 (344.2): C, 73.24; H, 4.68; N, 8.13.
Found: C, 72.78; H, 4.26; N, 8.23.
3.5.7. 3-(2-Ethoxyacetyl)-1-phenyl-1H-imidazo[1,2-a]-
pyridinium-2-olate (10f)
Ethanol was used; yield: 0.117 g (0.395 mmol, 79 %) mp: 178–
3.5.11. 1-Phenyl-3-2-(pyridinium)-1H-imidazo[1,2-a]pyridinium-2-
olate chloride (10j)
179 ꢀC; 1H NMR (200 MHz, CDCl3):
d
¼1.32 (t, J¼7.0 Hz, 3H, CH3CH2),
3.70 (q, J¼7.0 Hz, 2H, CH3CH2), 4.81 (s, 2H, CH2), 7.11–7.29 (m, 2H,
A sample of 0.2 mL (2.5 mmol) of pyridine was added to a solu-
tion of 0.143 g (0.5 mmol) of the betaine 6 and 5 mL of chloroform.
The reaction mixture was then refluxed for 4 h. After cooling to
room temperature the reaction mixture was extracted with 10 mL
of water. Evaporation of the solvent in vacuo gave a reddish solid.
Yield: 0.037 g (0.1 mmol, 20 %); mp: 185 ꢀC (dec); 1H NMR
Harom.), 7.45–7.65 (m, 6H, Harom.), 10.19 (d, J¼6.6 Hz, 1H, 5-H). 13C
NMR (50 MHz, CDCl3):
d
¼15.2 (CH3CH2), 61.0 (CH3CH2), 73.3 (CH2),
101.9 (C-3), 106.7 (C-8), 116.7 (C-6), 127.0 (2C, C-20), 129.3 (C-40),
129.7 (C-5), 130.0 (2C, C-30), 131.8 (C-10), 132.1 (C-7), 136.7 (C-9),
~
158.2 (C-2), 184.8 (C]O). IR (KBr):
n
¼ 3110, 3061, 2970, 2865,
1685, 1631, 1506, 1457, 1424, 1340, 1319, 1240, 1204, 1121, 1049, 901,
768, 713 cmꢁ1. MS: 297 [MþHþ](100), 252 (60), 237 (65), 181 (20),
77 (25). HR-ESI-MS: calcd for C17H17N2O3: 297.1239; found:
297.1240. Anal. cCalcd for C17H16N2O3 (296.32): C, 68.91; H, 5.44; N,
9.45. Found: C, 68.41; H, 5.06; N, 9.47.
(200 MHz, CDCl3):
7.50–7.73 (m, 5H, Harom.), 7.82–7.93 (m,1H, Harom.), 8.10–8.18 (m, 2H,
d
¼6.15 (s, 2H, CH2), 7.24–7.43 (m, 2H, Harom.),
b
-Py-H), 8.62–8.73 (m, 1H,
g
-Py-H), 8.96–9.00 (m, 2H,
a
-Py-H), 9.74
¼67.1 (CH2),103.0
-Py-C),
(d, J¼6.4 Hz,1H, 5-H). 13C NMR (50 MHz, CDCl3):
d
(C-3), 109.2 (C-8), 118.9 (C-6), 128.7 (2C, C-20), 128.8 (2C,
b